JP3132623B2 - Preventive maintenance device and preventive maintenance method for shroud - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preventive maintenance device for preventing a stress corrosion crack by improving a residual tensile stress existing in a metal material by jetting a liquid jet to a metal member of a nuclear reactor. In particular, alleviation and improvement of tensile residual stress existing in the welded parts of the lower core shroud, shroud support cylinder, shroud support leg, shroud support plate, and weld heat affected zone of the reactor internals of the BWR plant that started operation It relates to a preventive maintenance device suitable for achieving.

[0002]

2. Description of the Related Art As a method of alleviating a residual stress in a weld portion or the like which causes stress corrosion cracking, there is a technique disclosed in Japanese Patent Application Laid-Open No. 62-63614.

[0003] This is achieved by inserting a high-pressure water shot peening apparatus having a rotary nozzle section for jetting a high-pressure liquid jet into a tube of a heat exchanger or the like which is an object to be improved in residual stress,
By peening the inner surface of the pipe with the axial dynamic pressure energy of the jet itself (the axial dynamic pressure energy of the jet stream), tensile residual stress originally present in the pipe is converted into compressive residual stress.

There is also a technique disclosed in Japanese Patent Application Laid-Open No. Hei 5-78738, in which a water jet ejection head at the tip of a lower mast is constructed by opening a lower mast serving as an arm on an upper mast serving as a center pole. Face the shroud inside. Cavitation bubbles are generated by injecting a high-pressure jet from a water jet ejection nozzle of a water jet ejection head, and the cavitation bubbles collide with the inner surface of the shroud to improve the surface stress state.

[0005]

SUMMARY OF THE INVENTION The above Japanese Patent Application Laid-Open No. 62-63614
The prior art disclosed in Japanese Patent Laid-Open Publication No. H10-27146 is an effective method for improving the residual stress on the inner surface of a pipe such as a heat exchanger.However, it is work in the atmosphere that the axial dynamic pressure of a water jet can be effectively used.
In order to use this technology as a submerged water jet, the resistance of the surrounding water and the same liquid phase greatly reduce the jet shaft dynamic pressure, making it difficult to effectively obtain the peening effect. To obtain a dynamic pressure, jetting of a water jet at an extremely high pressure is required, which is disadvantageous in terms of the cost of the pump and related equipment.

[0006] Further, a lower part of a core shroud of a furnace internal structure, a shroud support cylinder,
It is difficult to apply to the shroud support leg and the shroud support plate because it is necessary to lower the reactor water level to the lower part of the internal structure of the furnace, and a decrease in the reactor water level leads to an increase in the ambient radiation dose rate.

The prior art disclosed in Japanese Patent Application Laid-Open No. Hei 5-78738 is an effective method for efficiently constructing the inner surface of the intermediate shroud body. However, in order to rotate the lower mast as an arm, all the neutron detectors are removed. There is a need.

Further, when applied to the lower core of the core shroud, the shroud support cylinder, and the shroud support leg, it is necessary to remove all control rods, fuel support fittings, control rod guide tubes, and the like. It cannot be said that it is more preferable.

Further, it is difficult to apply the present invention to a narrow portion such as a shroud support cylinder, an outer surface welded portion of a shroud support leg, and a shroud support plate in consideration of the accessibility of the apparatus.

SUMMARY OF THE INVENTION An object of the present invention is to be able to perform in an underwater atmosphere, and to provide a lower part of a core shroud, a shroud support cylinder, a weld of a shroud support leg, a shroud support cylinder, an outer weld of a shroud support leg, and a shroud support. A preventive maintenance device for a shroud that can efficiently perform improvement of residual surface stress that causes stress corrosion cracking in plate welds and
It is to provide a preventive maintenance method .

[0011]

SUMMARY OF THE INVENTION According to the present invention, preventive maintenance is performed.
Can be attached to the core support plate at the target core shroud lower body, shroud support cylinder, shroud support leg, and shroud support plate
Top attachment, attachable to CRD housing
Lower attachment, injection nozzle and its driving mechanism
Unit having nozzle and prevention device provided with device body
Using a maintenance device, the drive mechanism and the device body
The area between the core support plate and the CRD housing is
Up, down, rotate, swivel, front and back in the area
By expanding and contracting and moving the shroud in the circumferential direction,
Injecting a high-pressure jet (equivalent to furnace water quality) from the spill
The cavitation bubbles generated by the
By colliding with the surface, the surface residual stress at the target location
To improve. In this case, the residual stress, which is one of the factors causing stress corrosion cracking due to the collapse pressure of the cavitation bubbles, is improved.

Preferably, the circumferential direction of the injection nozzle
Rail used for movement is attached to the nozzle unit
The rail is connected to the upper grid plate and the core support plate.
And then rotate the rail by 90 °
Set in the circumferential direction of Udo, the circumferential direction of the injection nozzle
Make the move.

[0013]

According to the present invention, a preventive maintenance device is provided in which the core support plate and the CRD housing are provided with a drive mechanism for raising and lowering, rotating, turning, expanding and contracting, and moving in the circumferential direction. Cavitation bubbles are generated by the pressure difference between the surrounding water and the jet stream, shearing action, etc., and the shock pressure generated when the cavitation bubbles collapse causes the lower core shroud body, shroud support cylinder, shroud support leg,
And peening the surface of the shroud support plate to improve residual stress.

[0014] At this time, the drive nozzle of the preventive maintenance device is controlled to inject a high-pressure jet corresponding to reactor water quality into the injection nozzle for the lower part of the core shroud and the vertical weld of the shroud support cylinder. Peening the surface of the vertical weld to improve residual stress.

In each of the peripheral welds of the lower part of the core shroud, the shroud support cylinder, and the shroud support leg, the injection nozzle is moved to the nozzle running rail in the circumferential direction, and the lower part of the core shroud is injected while injecting a high pressure jet equivalent to the reactor water quality. The surface of the girth weld of each of the trunk, the shroud support cylinder, and the shroud support leg is peened to improve residual stress.

Also, by replacing the nozzle unit of the preventive maintenance device, the nozzle unit is passed between the shroud support legs by a telescopic or pantograph mechanism, and the nozzle unit is moved to the outer surface of the shroud support.

The spray nozzle rotates the rail in the nozzle unit by 90 ° and moves on the rail to form a shroud support cylinder, an outer surface welded portion of the shroud support leg, and a shroud support plate from the spray nozzle to a water quality equivalent to the reactor water quality. High pressure jet to peening the surface to improve residual stress.

Further , the preventive maintenance device accesses and sets narrow spaces such as spaces between lattices of the upper lattice plate and holes for control rod guide tubes in the core support plate.

After the setting, the rail for moving the spray nozzle in the circumferential direction is rotated by 90 °, and the spray nozzle is moved on the rail, thereby expanding the working range in the circumferential direction.

The injection nozzle peens the surface of the lower part of the core shroud, the shroud support cylinder, the shroud support leg, and the shroud support plate while jetting a high-pressure jet equivalent to the reactor water quality to improve residual stress. In addition, on the preventive maintenance equipment
Parts, more to replace the attachment portion is attached to the lower, in the cylindrical inner surface having a core shroud lower torso equivalent curvature to inject furnace water equivalent pressure jet from the injection nozzle, peened surface improved residual stress I do.

When a high-pressure jet is jetted from the injection nozzle, a reaction force is generated by the injection, and the injection reaction force becomes maximum when the injection nozzle moves to the rail end.

In order to receive the reaction force, the rail is provided with a support and a reaction force nozzle, thereby suppressing the reaction force, stably performing the work, extending the rail length, and expanding the work range.

[0023]

DETAILED DESCRIPTION FIG. 1 shows a nuclear power plant after starting operation.
FIG. 3 is a diagram illustrating a configuration of an example to which the present invention is applied .

Although not shown in the drawings, the lid of the reactor pressure vessel, the steam dryer, the steam separator, the fuel assembly, the control rod, the fuel support bracket, the control rod guide tube, and the like are sequentially removed.

The preventive maintenance device 1 is connected to a hoist crane 4 and a wire rope 5 of a refueling trolley 3 installed on the operating floor 2 of the reactor building.
The preventive maintenance device 1 is set at a predetermined position by moving and reversing the refueling trolley 3 and raising and lowering the hoist crane 4.

Although not shown, the preventive maintenance device 1 is set such that a base is set on the flange 7 of the reactor pressure vessel 6 and the base is rotatable about the center of the reactor pressure vessel 6 on the base. The turning platform and a movable platform which can be moved in the radial direction are provided on the upper surface of the rotating platform, respectively, and the movable platform is provided with an elevating device for raising and lowering the preventive maintenance device 1 in a predetermined position. May be.

The operation of setting the preventive maintenance device 1 is performed while monitoring the image of the monitoring camera 8.

The image of the monitoring camera 8 is displayed on a monitor 10 incorporated in the control panel 9, and shows the positional relationship between the device and the grids of the upper grid plate 11 and the holes 13 for the control rod guide tubes of the core support plate 12. Check the gaps in particular, and suspend the device so as to avoid interference.

Also, the positional relationship between the apparatus and other furnace internals and the elevation position of the apparatus are confirmed. Although the operator does not move the surveillance camera 8 in this drawing, the cable 14 of the surveillance camera 8 and the surveillance camera 8
This is performed by moving the rope 15 attached to the tip.

On the operating floor 2 of the reactor building, a control panel 9 for remotely controlling the preventive maintenance device 1 and a high-pressure pump 16 for supplying pure water equivalent to reactor water quality at a high pressure are installed.

Although not shown, the high-pressure pump 16 can also be installed at a place other than the operating floor 2 of the reactor building, for example, at a large cargo entrance of the reactor building or in an empty space inside the reactor building.

At this time, the high-pressure pump 16 and the preventive maintenance device 1
Is extended.

The control panel 9 transmits and receives a control cable 18 for transmitting and receiving an electric signal for remotely operating the preventive maintenance device 1, an air hose 19 for supplying air for remotely operating, and an electric signal for remotely operating the high-pressure pump 16. Each device is connected by a control cable 20 to remotely control each device.

The remote operation can be selected from a manual mode and an automatic mode. Basically, the construction is automatically performed.
The position adjustment and the like are manually performed.

Further, the control panel 9 moves the injection nozzle 21 up and down,
The operating speed and pitch of rotation, turning, longitudinal expansion and contraction, and circumferential movement can be adjusted to optimal values for construction.

Each drive mechanism will be described with reference to FIG.

The operating air for remotely operating the preventive maintenance device 1 is guided from the air supply source of the reactor building to the control panel 9 via the air hose 22, and the valve in the control panel 9 is controlled to control the preventive maintenance device 1. Remote control.

Although illustration is omitted, the air for remotely operating the preventive maintenance device 1 can be provided with a compressor other than the air supply source of the reactor building and supply air to the air hose 22.

In the configuration for supplying high-pressure pure water to the preventive maintenance device 1, pure water equivalent to reactor water quality is supplied to the high-pressure pump 16 through a low-pressure hose 23 from a pure water supply source of the reactor building, and the pressure is increased.

Although not shown, the pure water supplied to the high-pressure pump 16 is not limited to a pure water supply source of the reactor building, and is adjusted to a water quality that does not cause a problem even if ordinary water is introduced into the reactor. Pure water may be supplied via a water producing device.

As shown in FIG. 2, the high pressure pump 16 is circulated by the circulation pump 26 through the hose 25 and the filter 61 for removing the clad floating in the reactor water.
It is also possible to supply to.

In this case, the reactor water 24 is pressurized by the high-pressure pump 16, then injected from the injection nozzle 21 and returned to the furnace again to constitute a circulation system.

The pressurized pure water (reactor water 24 in the case of the circulation system in FIG. 2) is supplied to the preventive maintenance device 1 through the high-pressure hose 17.
Nozzle 2 attached to the preventive maintenance device 1
The cavitation bubbles 27 are generated by spraying from No. 1.

It should be noted that cavitation bubbles 2
The cladding containing radioactive iron oxide as a main component, which is rolled up from the collapse pressure of 7 and the water flow by the high-pressure water jet and causes an increase in atmospheric dose, is collected by a cladding collecting device 29 having a suction port 28.

The clad collecting device 29 includes a suction port 28, a clad transferring hose 30, and a clad transferring pump 31. The clad sucked together with the reactor water 24 is collected by a filter 32 in the clad collecting device 29.

The reactor water 24 collected together with the clad is returned to the spent fuel pool 34 via the discharge hose 33.

Although not shown, the filter 32 from which the clad has been recovered is packed as a highly radioactive waste in a container such as a drum with a shield, and stored in a nuclear power plant.

Among the cavitation bubbles 27 generated by the high-pressure water injection, those that reach the reactor water surface 35 without collapsing, when the radioactive cladding collapses at the reactor water surface 35, the contamination may occur. Since there is a risk of expansion, the air is collected by the air collecting cover 36 that covers the reactor water surface 35, and the air is exhausted to the existing ventilation air-conditioning exhaust duct 39 in the reactor building by the local exhaust device 38 via the transfer hose 37.

A filter 40 for collecting dust and mist is incorporated in the local exhaust device 38, and contaminants are collected here.

Although not shown, the filter 40 that has collected dust and mist is packed as radioactive waste in a container such as a drum and stored in a nuclear power plant.

The incidental In the above embodiment, the by cladding recovery device 29 and the local exhaust device 38, preventing the decontamination and contamination expansion of the reactor pressure vessel 6, the reduction of exposure dose is carried out simultaneously.

FIG. 2 shows the reactor water 2 described above as another embodiment.
4 shows a configuration diagram of a circulation system using No. 4 as injection water.

The system other than using the circulation pump 26 and supplying the reactor water 24 to the high-pressure pump 16 with the hose 25 is the same as in FIG.

FIG. 3 shows the main part of the present invention in FIGS. 1 and 2 around the bottom of the reactor pressure vessel 6 and around the lower part of the internal structure of the reactor, and shows a state where the preventive maintenance device 1 is set.

FIG. 4 shows details of the embodiment shown in FIGS .

First, the structure of the preventive maintenance device 1 includes an upper attachment 41 for setting the rotational direction of the preventive maintenance device 1 on the head, a rotation drive mechanism 42 for rotating the main body of the preventive maintenance device 1, and a preventive maintenance device thereunder. There is a main body of device 1 and C at the tip
The RD housing 43 includes a lower attachment 44 fixed to an opening in the head.

The main body of the preventive maintenance device 1 has a nozzle unit for driving the injection nozzle 21.

The preventive maintenance device 1 in this figure is set and fixed to the control rod guide tube hole 13 of the core support plate 12 and the CRD housing 43.

The fixing method is such that the positioning pin 4 on the core support plate 12 is supported laterally by the control rod guide tube hole 13.
The position in the rotation direction is determined by matching the notch 46 of the upper attachment 41 of the preventive maintenance device 1 with 5, and the construction start position of the injection nozzle 21 is determined.

Further, the lower attachment 44 of the preventive maintenance device 1 is inserted into the opening of the head of the CRD housing 43,
The CRD housing 43 is fixed to an opening in the head.

Next, the driving mechanism of the injection nozzle 21 will be described.

The injection nozzle 21 moves up and down, rotates, swivels, expands and contracts with respect to the lower core shroud 47, the shroud support cylinder 48, and the shroud support leg 49 in which the preventive maintenance device 1 is set. It can be moved in the circumferential direction by the directional running rail 50.

The rotation operation of the nozzle circumferential traveling rail 50 and the circumferential movement of the injection nozzle 21 will be described with reference to FIG.

[0064] Also, the details of the unit for constriction will be described with reference to FIG. 6.

The raising / lowering operation of the injection nozzle 21 is performed by rotating a lifting / lowering motor 52 mounted on the upper part of the main body of the preventive maintenance device 1 with the ball screw 51 mounted on the main body of the preventive maintenance device 1.

At this time, the guide is guided by a guide 53 attached inside the main body of the preventive maintenance device 1 and moves up and down smoothly and accurately.

The rotation of the injection nozzle 21 with respect to the axis of the preventive maintenance device 1 is omitted in FIG.
The gear inside is made by rotating the gear of the rotating motor.

The turning operation of the injection nozzle 21 is performed by turning a turning motor in the nozzle turning drive mechanism 54.

The back-and-forth expansion and contraction operation for adjusting the distance between the injection nozzle 21 and the construction target portion is performed by the rail rotation driving mechanism 5 that fixes the injection nozzle 21 and the nozzle circumferential traveling rail 50.
5 makes the rail 57 on the table 56 run by the cylinder, and expands and contracts back and forth.

The elevation motor 54, the rotation motor in the rotation drive mechanism 42, and the nozzle rotation drive mechanism 58 for driving the elevation, rotation, and rotation operations of the injection nozzle 21.
Each of the turning motors provided inside the motor has a detector such as a potentiometer for detecting the rotational position and speed, and the signals of the detectors are transmitted via a control cable 18 to a control panel 9.
The rotation of each motor is controlled under the optimum conditions of the scanning speed and the injection position (elevation position, rotation position, turning angle) of the injection nozzle 21 at the time of preventive maintenance construction.

The water pressurized by the high-pressure pump 16 is guided to the preventive maintenance device 1 through the high-pressure hose 17 and is jetted from the jet nozzle 21.

At this time, the cavitation bubbles 2 are generated by the pressure difference between the surrounding water (reactor water) 24 and the jet water flow, the shearing action, and the like.
7 is generated, and the entire target portion is peened by the impact pressure generated when the cavitation bubble 27 collapses on the lower surface of the furnace internal structure and its vicinity, thereby improving the residual stress.

The scan pattern of the injection nozzle 21 is based on the vertical weld position of the lower core shroud body 47 and the shroud support cylinder 48, and the circumferential weld position of the lower core shroud body 47, the shroud support cylinder 48 and the shroud support leg 49. It is managed in the control panel 9 in advance.

With respect to the position of the vertical weld, the vertical movement is repeated at the optimum construction speed in the axial direction and the rotational operation is repeated at the optimal pitch in the circumferential direction, and the injection nozzle 21 is turned at the corner.

Further, with respect to the position of the circumferential weld, the circumferential moving operation, the rotating operation, and the elevating operation at the optimum pitch in the axial direction are repeated at the optimum working speed in the circumferential direction.

With the above scanning pattern, SCC preventive maintenance of the welded portions of the lower core shroud body 47, the shroud support cylinder 48, and the shroud support leg 49 to be constructed is performed.

FIG. 5 shows details of the rotating operation of the nozzle circumferential traveling rail 50 and the rail circumferential moving operation of the injection nozzle 21.

The rail rotation of the nozzle circumferential running rail 50 is performed by rotating the nozzle circumferential running rail 50 that has been vertically placed at the time of storage by 90 ° by the rail rotation driving mechanism 55 on the table 56 attached to the ball screw 51. Let it.

Although not shown in the drawing, the rotation of the rail is transmitted by a worm wheel mounted on the rail shaft 58 by a worm gear.

The movement of the injection nozzle 21 in the rail circumferential direction is such that a high-pressure jet is injected while the injection nozzle 21 is moved to the rail 60 by the nozzle traveling drive mechanism 59.

FIG. 6 illustrates an embodiment of the nozzle unit.

The drawing shows when the nozzle unit is stored, when the nozzle unit is extended and retracted, and when the rail is rotated.

By replacing the nozzle unit of the preventive maintenance device with the nozzle unit according to this drawing, the injection nozzle 2
1 is an outer surface welded portion of a shroud support cylinder 48 and a shroud support leg 49 in a narrow portion which is a target portion;
In addition, it can move up and down, rotate, rotate, extend and contract back and forth with respect to the welded portion of the shroud support plate 62, and can move in the circumferential direction by the nozzle travel rail 63.

First, the arm 64 for moving the nozzle unit to the vicinity of the construction target position is extended.

This arm front-rear extension / contraction operation is driven by a telescopic mechanism.

Although not shown in the figure, a pantograph mechanism may be used.

The rotation of the nozzle running rail 63 is rotated by 90 ° by the rail rotation driving mechanism 65.

[0088] The vertical movement of the injection nozzle 21, the elevating motor 5 a ball screw 55 mounted on preventive maintenance apparatus 1 main body
Performed by rotating at 2.

[0089] Also the rotation operation of the injection nozzle 21, by rotating the gear of the rotation driving mechanism 42 by the gear of the rotary motor.

The turning and moving operation of the injection nozzle 21 is performed by rotating the turning motor in the nozzle turning / running drive mechanism 66 so that the injection nozzle 21 turns, and the running in the nozzle turning / running drive mechanism 66 is performed. The ejection nozzle 21 moves on the nozzle travel rail 63 by the driving mechanism.

It should be noted that the elevation, rotation, turning,
And a rotation motor for driving each operation of the rotation of the nozzle travel rail, a rotation motor in the rotation drive mechanism 42, a rotation motor in the nozzle rotation and travel drive mechanism 66, and a rotation for rotating the nozzle travel rail. Each motor is provided with a detector such as a potentiometer for detecting the rotational position and speed of each motor, and the signal is transmitted to the control panel 9 via the control cable 18 so that the scanning speed of the spray nozzle 21 and the spraying speed at the time of preventive maintenance work are performed. The rotation of each motor is controlled based on the optimal position (elevation position, rotation position, turning angle, rail rotation position).

The water pressurized by the high-pressure pump 16 is guided to the preventive maintenance device 1 via the high-pressure hose 17 and is jetted from the jet nozzle 21.

At this time, the cavitation bubbles 2 are generated due to a pressure difference between the surrounding water (reactor water) 24 and the jet water flow, a shearing action, and the like.
7, and the entire lower part of the target object is peened by the impact pressure generated when the cavitation bubble 27 collapses on the surface of the lower part of the furnace internal structure and in the vicinity thereof, thereby improving the residual stress.

The scanning pattern of the injection nozzle 21 is determined by the shroud support cylinder 48, the shroud support leg 4,
9 and the position of the welded portion of the shroud support plate 62 are managed in the control panel 9 in advance.

For the positions of the welded portions of the shroud support cylinder 48 and the shroud support legs 49, the circumferential moving operation at the optimum working speed in the circumferential direction and the elevating operation at the optimum pitch in the axial direction are repeated.

With respect to the position of the welded portion of the shroud support plate 62, the injection nozzle 21 is swirled to repeat the circumferential moving operation at the optimum working speed in the circumferential direction and the elevating operation at the optimum pitch in the axial direction.

By the above scanning pattern, the SCC preventive maintenance of the outer surface welded portions of the shroud support cylinder 48, the shroud support leg 49, and the welded portion of the shroud support plate 62 to be constructed is performed.

[0098] More Figure 7, will be described injection reaction force receiver mechanism rail is subjected.

The nozzle circumferential traveling rail 50 for moving the spray nozzle in the circumferential direction and the nozzle running rail 63 for the narrow portion receive an injection reaction force due to the high-pressure jet injection from the injection nozzle.

[0100] In contrast to this, the nozzle circumferential direction of the running rail 5
By providing a reaction force receiving support 67 for receiving the injection reaction force at the end of 0, the injection reaction force is suppressed, the rail length is increased, and the construction range in the circumferential direction is expanded.

A roller 69 is provided at the tip of the reaction force receiving support 67 to make it easy to move the rail up and down.

Further, the reaction force receiving support 67 has a structure in which it falls down when the nozzle rail 50 is retracted.

FIG. 8 shows an example of a device setting location.

In the nozzle traveling rail 63 for a narrow portion, as shown in FIG. 6, by providing a reaction force nozzle 68 which receives an injection reaction force after the injection nozzle 21, the injection reaction force is suppressed, and stable construction is achieved. It was decided to.

[0105] indicates those viewed in plan the furnace <br/> heart support plate 12 of the plant to apply the embodiment from above in FIG.

In this example plant, the control rod guide tube hole 13 of the core support plate 12 set in the preventive maintenance device 1
There are 37 places.

In the case of setting the preventive maintenance device 1 without rails, it is difficult to cope with the circumferential direction, so that the preventive maintenance device 1 needs to set the outer peripheral portion over the entire circumference.

If this is set for the preventive maintenance device 1 with a rail, it is possible to cope with the circumferential direction, so that the setting locations are 20 locations indicated by + as shown in the figure.

Further, if the preventive maintenance device 1 in which the rail is provided with the injection reaction force support is set, the number of set points becomes ten, and the circumference of each of the core shroud lower body, the shroud support cylinder, and the shroud support leg to be installed is set. The construction range in the direction can be expanded.

[0110]

According to the present invention, construction in an underwater atmosphere is possible.
Yes, core shroud lower body, shroud support silly
And shroud support leg welds, shura
Outer surface of UD support cylinder and shroud support leg
For welds and shroud support plate welds
Efficient improvement of surface residual stress, which is a factor in the occurrence of stress corrosion cracking
It can be constructed well.

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[Brief description of the drawings]

FIG. 1 is an overall view of a preventive maintenance device according to an embodiment of the present invention.

FIG. 2 is an overall view of a preventive maintenance device according to another embodiment of the present invention.

FIG. 3 is an elevation view showing a state in which a lower portion of the preventive maintenance device shown in FIGS. 1 and 2 is set in a reactor pressure vessel.

FIG. 4 is a detailed elevation view of the lower part of the preventive maintenance device shown in FIGS. 1 and 2;

5 is a plan view of the vicinity of the rail of the preventive maintenance device shown in FIG. 4; FIG. 5 (a) shows a state when the rail is stored;
The figure shows the situation when the rail is rotated 90 degrees.

FIGS. 6A and 6B are plan views of a nozzle unit for a narrow portion adopted in each embodiment of the present invention. FIG. 6A shows a state when the nozzle unit is stored, and FIG. 6B shows a state when the nozzle unit is extended. Is shown.

FIG. 7 is a plan view of an injection reaction force receiving mechanism employed in each embodiment of the present invention.

FIG. 8 is a plan view showing a set position of the preventive maintenance device in each embodiment of the present invention in a plane on a core support plate.

[Explanation of symbols]

1 ... preventive maintenance device, 2 ... operating floor, 3 ...
Refueling trolley, 4 ... Hoist crane, 5 ... Wire rope, 6 ... Reactor pressure vessel, 7 ... Flange, 8 ... Monitoring camera, 9 ... Control panel, 10 ... Monitor, 11 ... Upper grid plate,
12: core support plate, 13: hole for control rod guide tube, 14: cable, 15: rope, 16: high pressure pump, 17: high pressure hose, 18: control cable, 19, 22: air hose, 20: control cable, 21 ... injection nozzle, 23 ... low pressure hose, 24 ... reactor water, 25 ... hose, 26 ... circulation pump, 27 ... cavitation bubble, 28 ... suction port, 29
... Clad recovery device, 30 ... Clad transfer hose, 31
... Clad transfer pump, 32, 40, 61 ... Filter, 33 ... Discharge hose, 34 ... Spent fuel pool, 35
... furnace water surface, 36 ... air collecting cover, 37 ... transfer hose, 38
... Local exhaust system, 39 ... Exhaust duct for ventilation and air conditioning, 41 ...
Upper attachment, 42: rotary drive mechanism, 43: CR
D housing, 44: lower attachment, 45: positioning pin, 46: notch, 47: core shroud lower body, 48: shroud support cylinder, 49: shroud support leg, 50: nozzle circumferential running rail, 5
DESCRIPTION OF SYMBOLS 1 ... Ball screw, 52 ... Elevating motor, 53 ... Guide, 54 ... Nozzle turning drive mechanism, 55 ... Rail rotation drive mechanism, 56 ... Table, 57, 60 ... Rail, 58 ... Rail shaft, 59 ... Nozzle travel drive mechanism 62: shroud support plate, 63: nozzle travel rail, 64: arm, 65: rail rotation drive mechanism, 66: nozzle rotation /
Traveling drive mechanism, 67: reaction force receiving support, 68: reaction force nozzle, 69: roller.

Continued on the front page (72) Inventor Koichi Kurosawa 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor Noboru 2-13-1, Aise-cho, Hitachi-shi, Ibaraki Japan Ritsukiso Co., Ltd. (72) Inventor Fujio Yoshikubo 3-2-2, Sachimachi, Hitachi City, Ibaraki Prefecture Within Hitachi Nuclear Engineering Co., Ltd. (72) Inventor Kunio Enomoto 502, Kandamachi, Tsuchiura City, Ibaraki Prefecture, Ltd. Inside Hitachi Machinery Research Laboratory (72) Inventor Masahiro Otaka 502 Kandachicho, Tsuchiura City, Ibaraki Prefecture Inside Hitachi Machinery Research Laboratory (72) Inventor Kazunori Sato 3-36 Takaracho, Kure City, Hiroshima Prefecture Babcock Hitachi Co., Ltd. Inside Kure Research Laboratories (72) Inventor Eisaku Hayashi 3-1-1, Sachimachi, Hitachi, Ibaraki Pref.Hitachi, Ltd.Hitachi Plant (72) Inventor Ryo Morinaka 3-1-1, Sachimachi, Hitachi, Ibaraki Hitachi, Ltd.Investigator, Hitachi Works, Hitachi Plant Naohide Murata (56) Bibliography Patent flat 5-78738 (JP, A) JP flat 7-270590 (JP, A) JP flat 5-195052 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name G21C 19/02 G21C 13/00 G21D 1/00 JICST file (JOIS) WPI (DIALOG)

Claims (5)

(57) [Claims] 1. A shroud support leg fixed to a reactor pressure vessel by welding, a shroud support cylinder fixed to the shroud support leg by welding, and a cylindrical core shroud fixed to the upper end of the shroud support cylinder by welding. weld s lower torso respectively, the outer surface weld shroud support cylinder and the shroud support leg, as well as pre shroud performing preventive maintenance process on the shroud support plate welds
An upper attachment that can be attached to a core support plate and a CR.
A lower attachment that can be attached to the D housing
Nozzle unit having a firing nozzle and its driving mechanism
And an apparatus main body, wherein the injection nozzle includes the core support plate and the CRD housing.
The drive mechanism and the device in the area between
Using the main unit, lift, rotate, turn, extend and retract
The loudspeaker is configured to be able to move in the circumferential direction, and the high-pressure jet is jetted from the jet nozzle.
Ri cavitation bubbles caused, the core shroud lower cylinder is the target location, the shroud support cylinder, the shroud support leg, and by Rukoto collide with the surface of the shroud support plate, said target箇
Shroud characterized by improving surface residual stress in place
Preventive maintenance equipment . 2. The injection nozzle according to claim 1, wherein
Rails used for circumferential movement are attached to the nozzle unit
The rails, after passing through the upper grid plate and the core support plate,
Rotated by 90 ° and can be set in the circumferential direction of the shroud
Preventive maintenance equipment for shrouds
Place . 3. The method according to claim 1, wherein
Attachment and the lower attachment are replaceable
Shroud preventive protection characterized by having a structure
All devices . 4. A system fixed to a reactor pressure vessel by welding.
Shroud support leg, shroud support leg
Shroud support cylinder fixed by welding
And welding to the upper end of the shroud support cylinder
Welding of each fixed cylindrical core shroud lower body
Section, shroud support cylinder and shroud support
-External weld of the leg and shroud support
Of the shroud to perform preventive maintenance
Preventive maintenance method, upper attachment that can be attached to core support plate, CRD
Lower attachment, injection nozzle that can be attached to the housing
NOZZLE UNIT HAVING CHILL AND DRIVING MECHANISM
Using the preventive maintenance device provided with the apparatus main body, the core support by the drive mechanism and the apparatus main body.
In the area between the plate and the CRD housing,
Raising, lowering, rotating, turning, expanding and contracting and shroud the injection nozzle
The high-pressure jet is ejected from the ejection nozzle by moving the nozzle in the circumferential direction .
Cavitation bubbles generated in the target area
The core shroud lower body, shroud support syringe
Da, shroud support leg, and shroud support
Collision with the target plate
Shroud characterized by improving surface residual stress in place
Preventive maintenance methods . 5. The injection nozzle according to claim 4, wherein
Rails used for circumferential movement are attached to the nozzle unit
The rails are passed through the upper grid plate and the core support plate, and
After that, rotate the rail by 90 ° in the circumferential direction of the shroud.
Setting and performing the circumferential movement of the injection nozzle
Preventive maintenance device for shroud characterized by the following .